2008 Subaru Impreza 2.5i sedan (left) and hatchback Credit: Subaru
QUESTION: I bought my five-speed manual 2008 Subaru Impreza "wagon" about 1½years ago. It has about 20,000 km on it.
I have noticed that when I accelerate at anything greater than a leisurely pace, as soon as I take my foot off the gas and press down the clutch pedal to shift gear, the engine revs over the rpm it was at and then falls somewhat more slowly than I expect to a lower level.
The problem seems to have gotten a bit worse over the last six months. My gas usage has increased somewhat. I have taken the car in to the dealer three times now, including having the service manager drive with me in the car and note that what I reported is indeed happening.
The final answer is: "That's what the car is programmed to do and is supposed to do. Everything is computer-controlled nowadays [as with all cars] so we are not able to adjust this unless Subaru decides centrally that something should be changed and then puts it in a download we can apply to your car."
It doesn't make sense to me that this gas-wasting and performance-reducing approach is the way things are supposed to be. Is there some other story or solution available to me?
Andrew
ANSWER: Actually, this might well be quite the opposite of a "gas-wasting" approach.
As emissions standards become tighter, engineers have to resort to every little tweak they can find to minimize nasty stuff going out the tailpipe. In your case, I suspect the issue is that when you lift off the gas pedal the electronics maintain revs to ensure every last little bit of fuel is burned.
When the throttle is released suddenly, raw fuel on its way to the combustion chamber would otherwise be unused and result in added emissions. But by making sure it is burned before letting the revs drop, emissions are reduced and we all can breathe a little easier.
Gas use increasing
QUESTION: Could you please tell me whether I am in error suspecting that we may have been overcharged for a tank of gasoline today?
My 84-year-old wife is now the only driver of our 2003 Corolla and drives locally and only about 450 kilometres a month. The car receives all scheduled servicing etc. Its mileage is now 67,000 km. We always go to the same gas station and record our gas mileage. Today's figure seems very low.
I remember reading about how some dealers do adjust the meter so it reads higher than the advertised price per litre. I meant to check the charge at 10 litres but I was so cold I forgot.
Am I right to be suspicious and should wait till the next time to check the metered cost of exactly 10 litres? At 88 years and after a stroke early this year, I no longer drive.
John
Answer: I strongly doubt the dealer "fixed" or altered the pump to give a false reading. Gas pumps are highly regulated and inspected regularly by government officials - after all, the various levels of government have a vested interest in keeping these things honest because they want the tax money.
If anyone were to alter the pumps, there would be some serious legal issues and the company would be the first in line to punish the offender. The PR nightmare alone would be disastrous.
I suspect the real problem was a combination of two issues - weather and the previous fill. If the tank was not filled completely the previous time - i.e. to the same level as you regularly achieve - it would require more fuel to get it to that full point this time.
The automatic vent that shuts off the nozzle to prevent an overfill might have kicked in a little earlier or perhaps you didn't squeeze in that last few drops. It would only take a bit to make the difference.
Add to that the fact that cold weather can cause mileage to drop as much as 20 to 30 per cent and the combination might explain your variance.
Since you appear to keep records, what do they show for mileage during the depth of winter?